21053328 has 20 divisors (see below), whose sum is σ = 54387888. Its totient is φ = 7017760.

The previous prime is 21053323. The next prime is 21053353. The reversal of 21053328 is 82335012.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 21053298 and 21053307.

It is not an unprimeable number, because it can be changed into a prime (21053323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 219258 + ... + 219353.

Almost surely, 2^21053328 is an apocalyptic number.

It is an amenable number.

21053328 is an abundant number, since it is smaller than the sum of its proper divisors (33334560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21053328 is a wasteful number, since it uses less digits than its factorization.

21053328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 438622 (or 438616 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 21053328 is about 4588.3905675084. The cubic root of 21053328 is about 276.1257565962.

The spelling of 21053328 in words is "twenty-one million, fifty-three thousand, three hundred twenty-eight".